This invention relates to an electric apparatus having an opening formed to replace an electromagnetic wave noise generating source.
Recently, the development of the electric device field is so remarkable that the signal components and frequency components handled therein are many and various. Also, from another point of view, in order to reduce the weight and cost of the devices, the materials of the cases are changing from metals to plastic or the like. Under such circumstances, the obstacle by electromagnetic waves discharged from electric devices has become such a great problem that countermeasures against electromagnetic waves have been applied to electric devices. For example, a case made of plastic is painted on the inside with a shielding electroconductive paint so as to be conductive. Also, as in FIGS. 1 to 3, in the gap of an opening and closing door 2 provided in a case 1 or the jointing part between the case 1 and a front panel 3, such an electroconductive finger member 4 as is generally used for a shielding room opening and closing part and is shown in FIGS. 3(a)-3(b) is provided to intercept electromagnetic wave noise with the case outer fitting. The electromagnetic finger member 4 shall be explained in the following. The electroconductive finger member 4 shown in FIGS. 3(a)-3(b) has a band-like fitting part 4a and a plurality of finger parts 4b extending from the edge of this fitting part 4a and curved to be U-shaped as in FIG. 3(b).
The above mentioned fitting part 4a is fitted to the front panel 3 shown, for example, in FIGS. 3(a)-3(b) so that, when the front panel is fitted to the case 1, the finger parts 4b will be pressed against the case and will be elastically transformed so that the case 1 and front panel 3 may be positively electrically conductive.
FIG. 1 is a perspective view of an electric device. FIG. 2 is a sectioned view on line A--A' in FIG. 1. FIG. 3(a) is a plan view of an electroconductive finger member 4. FIG. 3(b) is a sectioned view on line B--B' in FIG. 3(a).
However, in the prior art shown in FIGS. 1 to 3(a)-3(b), the electromagnetic wave shielding effect is not sufficient and the appearance is ugly.
Also, in case an electromagnetic wave noise generating source and various circuits are provided within an electric apparatus, it will be necessary to shield the electromagnetic wave noise generating source on the periphery in order to reduce the influence of the electromagnetic wave noise on the circuit from the electromagnetic wave noise generating source but, in case the electromagnetic wave noise generating source is a lamp provided within a light source apparatus feeding an illuminating light, for example, to an endoscope, it will be necessary to replace the lamp due to a breakdown or the like and therefore an opening for the replacement will be provided in a shielding box. As a result, there has been a problem that the shielding can not be perfectly made.
In the publication of Japanese Utility Model Application Laid Open No. 23499/1987 is shown an art comprising a shielding case having an opening formed on one side surface, an electric part contained in this shielding case, a lid closing the opening of the shielding case, a recess through which are passed lead wires connected to the electric part formed in the opening of the shielding case and a shielding piece provided in this recess as substantially parallelly separated from and opposed to the inner surface of the lid. However, even in this prior art, the electromagnetic wave noise can not be well intercepted.